Metallic element and Protactinium

Metallic element noun - Any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc..

Protactinium and metallic element are semantically related. In some cases you can replace term "Protactinium" with "Metallic element", this terms are similar.

Protactinium noun - A short-lived radioactive metallic element formed from uranium and disintegrating into actinium and then into lead.

Metallic element and protactinium are semantically related. You can use "Metallic element" instead a noun "Protactinium".